Live imaging the phagocytic activity of inner ear supporting cells in response to hair cell death.

Hearing loss and balance disorders affect millions of people worldwide. Sensory transduction in the inner ear requires both mechanosensory hair cells (HCs) and surrounding glia-like supporting cells (SCs). HCs are susceptible to death from aging, noise overexposure, and treatment with therapeutic drugs that have ototoxic side effects; these ototoxic drugs include the aminoglycoside antibiotics and the antineoplastic drug cisplatin. Although both classes of drugs are known to kill HCs, their effects on SCs are less well understood. Recent data indicate that SCs sense and respond to HC stress, and that their responses can influence HC death, survival, and phagocytosis. These responses to HC stress and death are critical to the health of the inner ear. Here we have used live confocal imaging of the adult mouse utricle, to examine the SC responses to HC death caused by aminoglycosides or cisplatin. Our data indicate that when HCs are killed by aminoglycosides, SCs efficiently remove HC corpses from the sensory epithelium in a process that includes constricting the apical portion of the HC after loss of membrane integrity. SCs then form a phagosome, which can completely engulf the remaining HC body, a phenomenon not previously reported in mammals. In contrast, cisplatin treatment results in accumulation of dead HCs in the sensory epithelium, accompanied by an increase in SC death. The surviving SCs constrict fewer HCs and display impaired phagocytosis. These data are supported by in vivo experiments, in which cochlear SCs show reduced capacity for scar formation in cisplatin-treated mice compared with those treated with aminoglycosides. Together, these data point to a broader defect in the ability of the cisplatin-treated SCs, to preserve tissue health in the mature mammalian inner ear.

Cadmium affects metabolic responses to prolonged anoxia and reoxygenation in eastern oysters (Crassostrea virginica).

Benthic marine organisms such as mollusks are often exposed to periodic oxygen deficiency (due to the tidal exposure and/or seasonal expansion of the oxygen-deficient dead zones) and pollution by metals [e.g., cadmium, (Cd)]. These stressors can strongly affect mollusks' survival; however, physiological mechanisms of their combined effects are not fully understood. We studied the effects of Cd exposure on metabolic responses to prolonged anoxia and subsequent recovery in anoxia-tolerant intertidal mollusks Crassostrea virginica (eastern oysters). Anoxia led to an onset of anaerobiosis indicated by accumulation of l-alanine, acetate, and succinate. Prolonged anoxia (for 6 days) caused a decline in the maximum activity of electron transport chain and ADP-stimulated (state 3) oxygen uptake by mitochondria (MO(2)), but no change in the resting (state 4) MO(2) of oyster mitochondria, along with a slight but significant reduction of mitochondrial respiratory control ratio. During reoxygenation, there was a significant overshoot of mitochondrial MO(2) (by up to 70% above the normoxic steady-state values) in control oysters. Mild mitochondrial uncoupling during prolonged shutdown in anoxic tissues and a subsequent strong stimulation of mitochondrial flux during recovery may help to rapidly restore redox status and protect against elevated reactive oxygen species formation in oysters. Exposure to Cd inhibits anaerobic metabolism, abolishes reoxygenation-induced stimulation of mitochondrial MO(2), and leads to oxidative stress (indicated by accumulation of DNA lesions) and a loss of mitochondrial capacity during postanoxic recovery. This may result in increased sensitivity to intermittent hypoxia and anoxia in Cd-exposed mollusks and will have implications for their survival in polluted estuaries and coastal zones.

Perceptions of issues associated with the maintenance and improvement of long-term health in people with SCI.

STUDY DESIGN: Qualitative design using focus groups. OBJECTIVE: To explore the perceptions of people with SCI and their caregivers about information needs and service delivery options that may assist them to maintain or improve their long-term health. SETTING: Province wide project in Alberta, Canada. METHODS: Eight focus groups were conducted; five with community dwelling people with SCI and three with unpaid caregivers (family and friends). Content analysis was used to identify categories and themes arising from the data. RESULTS: The findings from the study are broader than the original objective to explore information needs and service delivery options to promote long-term health. The participants more globally discussed factors that contribute to or provide barriers to their long-term health. Those factors are captured in five categories, including readiness, information pathways, community health care, health promotion, and contextual factors. A framework that illustrates the relationships between categories was constructed. CONCLUSION: The framework identifies areas to target in programmes designed to reduce or prevent secondary conditions in people with SCI. SPONSORSHIP: This study was funded by the Alberta Paraplegic Foundation and the Glenrose Rehabilitation Hospital Foundation.

Generation of transgenic mice with mild and severe retinal neovascularisation.

AIM: To generate a mouse model for slow progressive retinal neovascularisation through vascular endothelial growth factor (VEGF) upregulation. METHODS: Transgenic mice were generated via microinjection of a DNA construct containing the human VEGF165 (hVEGF) gene driven by a truncated mouse rhodopsin promoter. Mouse eyes were characterised clinically and histologically and ocular hVEGF levels assayed by ELISA. RESULTS: One transgenic line expressing low hVEGF levels showed mild clinical changes such as focal fluorescein leakage, microaneurysms, venous tortuosity, capillary non-perfusion and minor neovascularisation, which remained stable up to 3 months postnatal. Histologically, there were some disturbance and thinning of inner and outer nuclear layers, with occasional focal areas of neovascularisation. By contrast, three other lines expressing high hVEGF levels presented with concomitantly severe phenotypes. In addition to the above, clinical features included extensive neovascularisation, haemorrhage, and retinal detachment; histologically, focal to extensive areas of neovascularisation associated with retinal folds, cell loss in the inner and outer nuclear layers, and partial retinal detachment were common. CONCLUSIONS: The authors generated four hVEGF overexpressing transgenic mouse lines with phenotypes ranging from mild to severe neovascularisation. These models are a valuable research tool to study excess VEGF related molecular and cellular changes and provide additional opportunities to test anti-angiogenic therapies.

Utilization of health services following spinal cord injury: a 6-year follow-up study.

STUDY DESIGN: Cohort study with 6-years follow-up. OBJECTIVE: To describe the utilization of health services by persons with spinal cord injury (SCI) and compare it with that of the general population. SETTING: Alberta, Canada. METHODS: All persons who sustained an SCI in Alberta between April 1992 and March 1994 were followed from date of injury to 6 years postinjury. Cases were matched (1:5) with controls randomly selected from the general population and matched for age, gender, and region of residence. Administrative data from centralized health care databases were compiled to provide a complete picture of health care use, including hospitalizations, physician contacts, long-term care admissions, home care services, and the occurrence of secondary complications. RESULTS: In all, 233 individuals with SCI and 1165 matched controls were followed for 6 years. Compared with the control group, persons with SCI were rehospitalized 2.6 times more often, spent 3.3 more days in hospital, were 2.7 times more likely to have a physician contact, and required 30 times more hours of home care services. Of those with SCI, 47.6% were treated for a urinary tract infection, 33.8% for pneumonia, 27.5% for depression, and 19.7% for decubitus ulcer. CONCLUSION: SCI places a heavy burden on the health care system. Persons with SCI have greater rates of contact with the health system compared with the general population. Secondary complications continue to affect persons with SCI long after the acute trauma.

Measuring quality of life of persons with spinal cord injury: external and structural validity.

STUDY DESIGN: Measurement evaluation of the external and structural components of validity. OBJECTIVES: To examine the relationships between quality of life (QOL) as measured by the spinal cord injury (SCI) version of the Ferrans and Powers Quality of Life Index (QLI) and other constructs represented within the model of disablement; and to examine the domains and scoring model of the QLI by exploring item and overall score/section score relationships. SETTING: Community, Alberta, Canada. METHODS: A convenience sample of 98 individuals with SCI living in the community completed the QLI and measures representing the model of disablement including the ASIA motor index, Functional Independence Measure, Reintegration to Normal Living index, Rosenberg's Self-Esteem Scale and Rotter's Internal-External Locus of Control scale. RESULTS: Four of the five a priori hypotheses were supported. Locus of control was not significantly related to QOL as expected. Factor analysis resulted in a five-factor structure that differed from the four-domain model of the original QLI. Scoring relationships indicated that both the satisfaction and importance ratings contribute to the overall score, although not equally. CONCLUSION: There is support for the external component of validity although further examination regarding locus of control for persons with SCI is warranted. The structural component of validity requires further investigation to elucidate the domains of the SCI version of the QLI and the contribution of the importance scores.

Relationship of tumour necrosis factor alpha gene polymorphisms and neuropsychiatric lupus.

Systemic lupus erythematosus (SLE) is a multisystem disorder which appears to be influenced by genetic make-up. In this study we determine allele frequency and genotype distribution of TNFalpha polymorphisms in two populations of SLE patients (with and without neuropsychiatric manifestations) in order to determine whether the rare allele (TNF2) confers susceptibility for neuropsychiatric disease in SLE. Patients with SLE were retrospectively reviewed to determine presence (n = 17) or absence (n = 47) of documented neuropsychiatric manifestations attributable to SLE. The DNA from these patients was extracted from peripheral blood mononuclear cells, and PCR amplification, NcoI enzyme digestion and 10% polyacrylamide gel electrophoresis were performed to define the different TNFalpha alleles. Two alleles were demonstrated, TNF1 (wild-type) and TNF2 (rare type), with three possible genotypes, TNF1,1, TNF1,2 and TNF2,2. A frequency of 24% was found for the TNF2 patients with neuropsychiatric involvement and was not statistically different to a frequency of 28% found in SLE patients without neuropsychiatric manifestations. The TNF-2 allele does not confer susceptibility for neuropsychiatric manifestations in SLE patients.

Comparative denaturing gradient gel electrophoresis analysis of fungal communities associated with whole plant corn silage.

Significant portions of grain produced for livestock consumption are convened into ensiled forage. Silage producers have long recognized the positive effects of using an inoculant to insure the proper transformation of forage into a palatable and digestible feedstuff. When silage is fed from a storage structure, exposure to air stimulates the growth of epiphytic aerobes that may result in the loss of up to 50% of the dry matter. Moreover, fungi have been found to be associated with ensiled forage, but their growth is normally suppressed by the anaerobic conditions. However, the introduction of oxygen results in a fungal bloom, and the fungi and the associated metabolites may result in lost productivity in the livestock consuming the contaminated forage. In this study, we report on the diversity of the fungal community associated with whole plant corn silage during the ensiling process, and the effect of two different bacterial inoculants as compared with the uninoculated natural epiphytic fermentation on the distribution of the fungi associated with the silage. The fungal community from duplicate mini-silo packages of the same treatment was analyzed by denaturing gradient gel electrophoresis and direct sequencing of the resulting operational taxonomic units. This method proved useful in analyzing the complex microbial communities associated with the forage in that it was possible to determine that one inoculant dramatically influenced the fungal community associated with whole plant corn silage.

Measuring quality of life of persons with spinal cord injury: substantive and structural validation.

The purpose of this study was to evaluate the substantive and structural validity of an existing measure of quality of life (QOL), the spinal cord injury (SCI) version of the Ferrans and Powers quality of life index (QLI). To evaluate substantive validity, 11 individuals with a SCI participated in 'think aloud' interviews to determine meaningfulness of the QLI items and to identify areas requiring modification. Free sort and ranking exercises of the items were used to evaluate the structural validity of the domains and scoring rubric. Content analysis of the interview comments resulted in the addition of two items and wording revision to three items. The free sort exercise revealed that the domains as perceived by the participants differed somewhat from those of the test developer. The contribution of the satisfaction and importance sections proposed by the scoring model was not completely supported by the data from the ranking exercise. It is concluded that the modified version of the QLI reflects the perspectives of persons with SCI spinal cord injury as represented by the participants of this study. The structural validity evaluation has implications for the use of domain subscores and weighted vs. section scores. Further evaluation of the modified version is necessary before widespread use with this patient population.

Assessment of isokinetic and hand-held dynamometer measures of shoulder rotator strength among individuals with spinal cord injury.

OBJECTIVE: To determine the intrarater reliability of the hand-held dynamometer (HHD) for the measurement of shoulder rotation and to examine the relationship between the peak force values of the HHD and the isokinetic dynamometer. PARTICIPANTS: Twenty-five spinal cord injured individuals, 12 persons with paraplegia and 13 persons with tetraplegia between the ages of 18 and 42 years, were recruited from the community. SETTING: Private practice clinic. PROCEDURES: All participants were tested with the HHD by one examiner to determine reliability. On the same day, these participants underwent isokinetic testing to determine the relationship of the HHD and Cybex dynamometer measurements. RESULTS: The intraclass correlation coefficients for the intrarater reliability ranged from .89 to .96. The Pearson product moment correlation was used to analyze the relationship between the two devices. All coefficients (.52 to .88) were statistically significant (p < .01); however, separate analyses for the persons with paraplegia and tetraplegia differed considerably. There was substantial variability of the isokinetic strength values at the lower levels of isometric strength. CONCLUSIONS: The HHD can be used reliably to measure shoulder rotation in paraplegic and tetraplegic spinal cord injured individuals. Although it appears that the relationship between HHD and isokinetic measurement is poor for the participants with tetraplegia, the variability of the isokinetic scores indicates that this observation may be a function of the method of isokinetic measurements. Further study with a modified isokinetic testing protocol is needed to clarify the results of the participants with tetraplegia.

The senescent cataract patient: a management philosophy.

Senescent cataracts are a frequently encountered anomaly in optometric practice. Optometric management of these patients is an ongoing process only beginning with the physical diagnosis and encompassing necessary patient education, counseling, and advocacy.

Introduction of ambulatory medical training in a Veterans Administration hospital.

Planners of postgraduate medical education in the United States have mandated that training programs include experience in continuing patient care in the ambulatory setting. Idiosyncratic administrative features and limitation of resources present relatively unique problems for the development of such programs in Veterans Administration teaching hospitals. The authors describe the implementation of a continuity of care clinic in a highly subspecialized large VA internal medicine training program. Crucially, all residents attend the clinic on the same day. The internal medicine educational program was altered to prevent conflict of the new clinic with other teaching activities. The program has been well received by the involved house staff members and has achieved some of the intended goals.